What Is The Difference Between Using Pure Water And Tap Water For Anodic Oxidation Washing?

Aluminum anodizing process: mechanical polishing -- oil removal -- water washing -- chemical polishing -- water washing -- anodizing -- water washing -- closed -- mechanical bright chemical polishing products: aluminum alkaline polishing liquid anodizing products: aluminum anodizing liquid closed products: Aluminum anodizing and dyeing process Aluminum products treated with dyeing method have beautiful color, bright color, corrosion resistance, wear resistance and insulation than ordinary aluminum products. The aluminum workpiece is suspended in an appropriate electrolyte solution to act as an anode for electrolysis. In the process of electrolysis, hydroxide ions in water release electrons in the anode to become water and new ecological oxygen, which oxidizes aluminum into a thicker alumina film. Because this process is metal products as the anode is oxidized, so it is called anodic oxidation. After anodic oxidation, aluminum products can be dyed, sealed and treated. 1. Pretreatment: aluminum parts are stained with more oil, a small amount of abrasive, dust and defective oxide film in the process of mechanical processing. These substances have poor electrical conductivity and can not be anodized, so they need to be treated in advance. The method is to use carbon tetrachloride, trichloroethylene, gasoline or toluene as cleaning agent, the aluminum parts are immersed, washed with a brush, then air dry, then immersed in water, and cleaned many times. Rinse with hot water immediately after the oil is gone. If a black film is formed on the surface, soak it in 32% nitric acid solution for 20 seconds to remove the black film, and rinse it off with cold water. Immersed in distilled water for preparation of oxide film. 2. Anodic oxidation: ⑴ Sulfuric acid electrolyte preparation: by sulfuric acid 18-20 kg and deionized water 80-82 kg of mixed, at this time the specific gravity of the solution is about 1.125-1.140. A small amount of oxalic acid is usually added to sulfuric acid electrolyte in order to obtain a good protective oxygen electrode oxide film. (2) Oxidation process: the line meter is installed, the stained aluminum parts are used as the anode and all immersed in the electrolyte, and then the power is switched on, according to the following process conditions control. The electrolyte temperature is controlled at 12-25℃, the anode current density is 1-2 a/decimeter 2, and the voltage in the tank is between 13-23 volts. The time is about 30-40 minutes. According to the above process, at any time to remove the aluminum from the electrolyte, the acid stained with clean water, the concave part should pay more attention to, otherwise there will be white spots. After cleaning the acid solution, dip it into clean water and set aside. 3. Staining: After anodic oxidation, the surface of aluminum parts forms adsorption, which is bonded by covalent bond or hydrogen bond to form colored complexes, resulting in color. 1. Selection of dyes: inorganic dyes and organic dyes. Inorganic dyes are mostly composed of inorganic salts. When dyeing, aluminum parts are soaked in A and B compound solutions to generate colored compounds to achieve the purpose of dyeing. Inorganic dyeing solution Dye color solution A solution B Dyeing compounds Name Name Concentration Name Concentration Blue or light blue potassium ferricyanide 10-50 ferric chloride 10-100 Prussian blue brown potassium ferricyanide 10-50 copper sulfate 10-100 copper ferricyanide black cobalt acetate 50-100 potassium permangoate 15-25 Cobalt oxide yellow Potassium dichromate 50-100 Lead acetate 100-200 Lead dichromate gold baking soda 10-50 Lead permanganate 10-50 manganese trioxide white lead acetate 10-50 sodium sulfate 10-50 lead sulfate orange yellow aluminum lead acid 5-10 silver nitrate 50-100 There are a wide variety of organic dyes of silver chromate. The commonly used dyes, the concentration of dye solution and the color list are described below for reference. Dye color Dye Name Dye Concentration Remarks Yellow acid medium RH direct yellow brown D3G alcohol-soluble yellow GR direct frozen yellow G 0.7-11-50.5-11-2 All acidic dyes should be added with acetic acid 1-2 ml to adjust pH using alcohol as solvent yellow alizarin yellow indy orange acid orange H 1-211-2 The dye dyeing must add 10 grams of sodium nitrite, a liter of warm water with dyeing solution, dyeing time 30 minutes, and then 25 milliliters of sulfuric acid in a liter of warm water color for one minute. Red direct fast light peach G acid red GR alizarin red S 2-55-105-10 red alkaline rose essence Acid Orange Ⅱ 0.753 The two dyes were dissolved respectively and combined into A litre grass green direct fast light emerald green direct green B 3-52-5 blue direct fast light emerald blue GL active brilliant blue acid lake blue V acid lake blue A ⑵ Dyeing operation: ① Dyeing monochrome method: the anodized aluminum products are washed with clean water and immediately immersed in the coloring solution at 40-60℃. Soaking time: 30 seconds to 3 minutes for light color; Dark, black 3-10 minutes. Remove after dyeing and rinse with clean water. (2) Dyeing multi-color method: if dyeing two or more different colors on the same aluminum piece, or printing landscape, flowers and birds, characters, characters, the procedures are very complicated, there are coating masking method, direct printing and dyeing method, foam plastic dyeing method and so on. The above methods differ in operation, but the principle is the same. Now the coating masking method is introduced as follows: This method is mainly the fast dry and easy to clean the varnish thin and evenly coated in the real need of yellow, cover it up. When the film is dry, all the aluminum parts are immersed in dilute chromic acid solution to recede the yellow part of the unpainted varnish, remove it, wash it with clean water to remove the acid, dry it at low temperature, and then dye it red. If you want to dye the third and fourth colors, you can operate according to the above method. 4. Sealing: After the stained aluminum parts are washed with water, immediately put in 90-100℃ distilled water for 30 minutes. After this treatment, the surface becomes uniform without pores, forming a dense oxide film. The dye coated by coloring is deposited in the oxide film and can no longer be wiped off. The closed oxide film no longer has the adsorption property, and the wear resistance, temperature resistance and insulation have been strengthened. Will be closed after the surface of the aluminum parts dry, and then use a soft cloth to polish, you can get beautiful bright aluminum products, such as dyeing multi-color, closed treatment, should be the protective agent on the aluminum parts to remove, small area with cotton stained acetone wipe, large area can be stained aluminum parts immersed in acetone paint to wash away. 1. After oil washing treatment, aluminum parts should be oxidized immediately and should not be placed for too long. When aluminum parts are made of oxide film, they should all be immersed in the electrolyte, and the tank voltage should be stable and consistent from beginning to end. The same batch of products must be completely consistent, which should be followed even when dyeing. 2. In the process of anodic oxidation, the aluminum, copper, iron in the electrolyte solution is increasing, affecting the luster of aluminum. Electrolyte replacement should be considered when aluminum content is greater than 24 g/l, copper content is greater than 0.02 g/l, and iron content is greater than 2.5 g/l. 3. Buy raw materials and dyes to choose products with high purity, because the general impurity is a little more or mixed with tin powder, dextrin, dyeing effect is not good. 4. When dyeing a large number of dyes, the dye solution will be thick after the light, the color will appear different shades, so attention should be paid to mixing slightly thick dye solution at the right time, as far as possible to maintain the consistency of the dye solution concentration. 5. When dyeing multiple colors, light color should be dyed first and dark color should be dyed in order of yellow, red, blue, brown and black. Before dyeing the second color, the spray paint should be dry, so that the paint is close to the aluminum surface, otherwise the dye will be immersed, and the boundary of the raw edge is unknown. 6. Impurities in aluminum affect staining: silicon content is more than 2.5%, the bottom film appears gray, it is appropriate to dye dark. More than 2% magnesium, dull stain. Manganese in color tender, but not bright. Copper - containing tone band dull, too much iron, nickel, chrome color dull

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